Stochastic Analysis of Temperature Distribution in a Solid With Random Heat Conductivity

1988 ◽  
Vol 110 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Da Yu Tzou
Keyword(s):  
Thermal Conductivity ◽  
Temperature Distribution ◽  
Heat Conductivity ◽  
Stochastic Analysis ◽  
Solid Medium ◽  
Mean Value ◽  
Random Response ◽  
Thermal Failure ◽  
Numerical Examples ◽  
The Mean

Stochastic temperature distribution in a solid medium with random heat conductivity is investigated by the method of perturbation. The intrinsic randomness of the thermal conductivity k(x) is considered to be a distribution function with random amplitude in the solid, and several typical stochastic processes are considered in the numerical examples. The formulation used in the present analysis describes a situation that the statistical orders of the random response of the system are the same as those of the intrinsic random excitations, which is characteristic for the problem with extrinsic randomness. The maximum standard deviation of the temperature distribution from the mean value in the solid medium reveals the amount of unexpected energy experienced by the solid continuum, which should be carefully inspected in the thermal-failure design of structures with intrinsic randomness.

Random response of dielectric elastomer balloon to electrical or mechanical perturbation

2016 ◽  
Vol 28 (2) ◽  
pp. 195-203 ◽  
Author(s):  
Xiaoling Jin ◽  
Zhilong Huang
Keyword(s):  
Joint Probability ◽  
Stochastic Averaging ◽  
Stretch Ratio ◽  
Dielectric Elastomer ◽  
Mean Value ◽  
Rate Of Change ◽  
Random Response ◽  
First Case ◽  
Special Cases ◽  
The Mean

Random response of dielectric elastomer balloon disturbed by electrical or mechanical fluctuation is analytically investigated in this article. The stochastic differential equation governing the oscillating behavior around the stable equilibrium position is first derived by introducing the translation transformation. The stationary joint probability density about the disturbing stretch ratio and its rate of change is analytically established by adopting the stochastic averaging of energy envelope; the statistics quantities, such as the mean value and the standard deviation of the disturbing stretch ratio, are then subsequently calculated. Two special cases, the first case with only voltage fluctuation and the second one with only pressure variation, are discussed in detail, and the random response properties are summarized. The accuracy of the analytical solution is verified by comparing with the Monte Carlo simulation for the perturbation with weak intensity, and the valid ranges for the mean voltage and pressure are illustrated. This work provides an effective technique to evaluate the detection precision of new type of sensors based on the dielectric elastomer.

scholarly journals Static component of photothermal response in non-transparent samples

2012 ◽  
Vol 25 (3) ◽  
pp. 213-224 ◽  
Author(s):  
Zlatan Soskic ◽  
Slobodanka Galovic ◽  
Nebojsa Bogojevic ◽  
Slobodan Todosijevic
Keyword(s):  
Temperature Distribution ◽  
Mean Value ◽  
Optical Absorption Coefficient ◽  
Back Side ◽  
One Dimensional ◽  
Static Component ◽  
Special Cases ◽  
Static Part ◽  
The Mean ◽  
Analytical Expressions

The paper presents the analysis of the static component of temperature distribution in non-transparent samples during photothermal measurements. Analytical expressions for static part of temperature distribution in the irradiated sample and in its surroundings are determined using one dimensional model of heat transfer in a typical photothermal environment. It is established that the dominant factors that influence the shape and the mean value of the temperature distribution are optical absorption coefficient and thermal conductances of the sample and the surroundings. Important special cases are described and analytical expressions for temperatures of the front and the back side of the sample are derived.

scholarly journals Relationship between fiber diameter and performance of yak wool

2021 ◽  
Vol 33 (2) ◽  
pp. 20-24
Author(s):  
Baigalmaa Danzan ◽  
Sereeterdorj Dugerragchaa ◽  
Naransolongo Ukhnaa ◽  
Khishigjargal Tsedev
Keyword(s):  
Thermal Conductivity ◽  
Contact Angle ◽  
Evaluation Method ◽  
Fiber Diameter ◽  
Thermal Sensitivity ◽  
Mean Value ◽  
The Mean ◽  
The Difference ◽  
High Level ◽  
Correlation Level

This article demonstrates the thermal sensitivity and conductivity as well as the water permeability and absorptivity of Mongolian yak wool surfaces according to the Kawabata evaluation method. According to the results of the study, the mean value of thermal sensitivity (Qmax) of yak wool surface is 0.051 w/cm2 for down and 0.061 w/cm2 for coarse hair while the mean value of thermal conductivity is 2.08x10-4 (cal/cm ·0C) for down and 2.63x10-4(cal/cm · 0C) for coarse hair. This study, with its high level of confidence (p = 0.05), proves the difference between down and coarse hair. Additionally, the study shows a strong correlation between the thermal conductivity and the fiber diameter of Mongolian yak wool, resulting in a correlation level of r = -0.80 for down and r = 0.86 for coarse hair.   When measuring the wettability of Mongolian yak wool, yak wool surface exhibited waterproof properties with a contact angle of 146.50 degrees for down hair and a contact angle of 147.10 degrees for coarse hair. The study also revealed a low correlation level of r = 0.39 for down and r = 0.40 for coarse hair when examining the relationship between the contact angle and the diameter of yak wool.

scholarly journals A New Method for Defuzzification and Ranking of Fuzzy Numbers Based on the Statistical Beta Distribution

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
A. Rahmani ◽  
F. Hosseinzadeh Lotfi ◽  
M. Rostamy-Malkhalifeh ◽  
T. Allahviranloo
Keyword(s):  
Beta Distribution ◽  
Granular Computing ◽  
Fuzzy Numbers ◽  
Mean Value ◽  
Human Reasoning ◽  
Fuzzy Information ◽  
Numerical Examples ◽  
Novel Method ◽  
The Mean ◽  
Ranking Of Fuzzy Numbers

Granular computing is an emerging computing theory and paradigm that deals with the processing of information granules, which are defined as a number of information entities grouped together due to their similarity, physical adjacency, or indistinguishability. In most aspects of human reasoning, these granules have an uncertain formation, so the concept of granularity of fuzzy information could be of special interest for the applications where fuzzy sets must be converted to crisp sets to avoid uncertainty. This paper proposes a novel method of defuzzification based on the mean value of statistical Beta distribution and an algorithm for ranking fuzzy numbers based on the crisp number ranking system on R. The proposed method is quite easy to use, but the main reason for following this approach is the equality of left spread, right spread, and mode of Beta distribution with their corresponding values in fuzzy numbers within(0,1)interval, in addition to the fact that the resulting method can satisfy all reasonable properties of fuzzy quantity ordering defined by Wang et al. The algorithm is illustrated through several numerical examples and it is then compared with some of the other methods provided by literature.

scholarly journals O przewodności cieplnej meteorytu Jezersko

Nafta-Gaz ◽  
2021 ◽  
Vol 77 (1) ◽  
pp. 10-19
Author(s):  
Marian A. Szurgot ◽  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Geometric Mean ◽  
Mean Value ◽  
Air Pressure ◽  
Ordinary Chondrites ◽  
K Value ◽  
The Mean ◽  
Predicted Values ◽  
Bulk Thermal Conductivity

The thermal conductivity (K) of Jezersko H4 meteorite was predicted by various models of rocks, using literature data on the chemical composition, porosity (P), and by relationships between thermal conductivity and porosity, and between thermal conductivity and thermal diffusivity (D). The results confirm that the porosity of the chondrite and air pressure significantly affect thermal conductivity. The thermal conductivity of the chondrite skeleton/matrix predicted by the modal composition of the meteorite and by the geometric mean model is equal to 4.35 W m−1 K−1, and by arithmetic and harmonic mean models: 4.9 W m−1 K−1at 300 K. Bulk thermal conductivity of the meteorite predicted by the geometric mean model is equal to 2.6 W m-1 K-1 for air pressure of 1 atm, and 1.0 W m−1 K−1in vacuum at 300 K. The Hashin–Shtrikman model predicts the values: 2.4 and 1.9 W m−1 K−1, the Clausius–Mossotti model: 2.2 and 1.9 W m-1 K-1, and the mean of two-layer models: 2.1 and 2.0 W m−1 K−1 at 300 K, for air pressure of 1 atm, and in vacuum, respectively. The relationships between thermal conductivity and porosity based on experimental data for ordinary chondrites indicate a mean K value for bulk thermal conductivity of the Jezersko meteorite in vacuum: 1.18 W m−1 K−1, and between thermal conductivity and thermal diffusivity the mean value: 1.12 W m−1 K−1at 200–300 K. The mean value for all predictions for bulk thermal conductivity of the meteorite for air at 1 atm is equal to 2.45 ± 0.30 W m−1 K−1 (range: 2.0–2.9 W m−1 K−1) at 300 K, and in vacuum: 1.40 ± 0.40 W m−1 K−1 (range: 0.95–2.0 W m−1 K−1) at 200–300 K. Predicted values of bulk thermal conductivity of the Jezersko meteorite, for air and in vacuum, are in the range of values recently reported by Soini et al. (2020) for the H4 group of chondrites: 2.8 ± 0.6 W m−1 K−1, mean K for air at 1 atm, and 1.9 ± 1.0 W m−1 K−1 mean K value in vacuum at 200–300 K.

Study on Thermal Performance for Straw Fiber Concrete Hollow Block

2014 ◽  
Vol 953-954 ◽  
pp. 1596-1599 ◽  
Author(s):  
Zu Peng Zhang ◽  
Shui Wen Zhu ◽  
Guo Ping Chen
Keyword(s):  
Thermal Conductivity ◽  
Temperature Distribution ◽  
Thermal Performance ◽  
Building Block ◽  
Plant Fiber ◽  
Coefficient Of Thermal Conductivity ◽  
Fiber Concrete ◽  
Hollow Block ◽  
Insulation Effect ◽  
The Mean

In this paper, based on ansys studies for thermal performance of concrete hollow block which were conducted on the content of 5% and 15% of the straw plant fiber, and get temperature distribution and the law of heat of the blocks which suffer the load of convection, then calculate the mean coefficient of thermal conductivity and thermal resistance based on the data block obtained. The results show that mixed plant fiber can effectively improve thermal performance for the concrete hollow block,and better insulation effect,thus can provide the basis for the promotion of plant fiber building block materials.

Long-period modulated superstructures in Pd-12.5 at.%Ce and Pd-15 at.%Ce alloys

1990 ◽  
Vol 48 (4) ◽  
pp. 164-165
Author(s):  
Noriyuki Kuwano ◽  
Masaru Itakura ◽  
Kensuke Oki
Keyword(s):  
Electron Microscopy ◽  
Mean Value ◽  
Heavy Elements ◽  
Arc Furnace ◽  
X Ray ◽  
Long Period ◽  
Ultra High Purity ◽  
Heat Treated ◽  
Atomic Scattering ◽  
The Mean

Pd-Ce alloys exhibit various anomalies in physical properties due to mixed valences of Ce, and the anomalies are thought to be strongly related with the crystal structures. Since Pd and Ce are both heavy elements, relative magnitudes of (fcc-fpd) are so small compared with <f> that superlattice reflections, even if any, sometimes cannot be detected in conventional x-ray powder patterns, where fee and fpd are atomic scattering factors of Ce and Pd, and <f> the mean value in the crystal. However, superlattices in Pd-Ce alloys can be analyzed by electron microscopy, thanks to the high detectability of electron diffraction. In this work, we investigated modulated superstructures in alloys with 12.5 and 15.0 at.%Ce.Ingots of Pd-Ce alloys were prepared in an arc furnace under atmosphere of ultra high purity argon. The disc specimens cut out from the ingots were heat-treated in vacuum and electrothinned to electron transparency by a jet method.

Partition Coefficient Ratios and Tumour Perfusion Studied with 85mKr and 133Xe

1987 ◽  
Vol 26 (06) ◽  
pp. 253-257
Author(s):  
M. Mäntylä ◽  
J. Perkkiö ◽  
J. Heikkonen
Keyword(s):  
Partition Coefficient ◽  
Partition Coefficients ◽  
Regional Blood Flow ◽  
Blood Perfusion ◽  
Compartmental Analysis ◽  
Malignant Tumour ◽  
Mean Value ◽  
Perfusion Rate ◽  
Biological Variables ◽  
The Mean

The relative partition coefficients of krypton and xenon, and the regional blood flow in 27 superficial malignant tumour nodules in 22 patients with diagnosed tumours were measured using the 85mKr- and 133Xe-clearance method. In order to minimize the effect of biological variables on the measurements the radionuclides were injected simultaneously into the tumour. The distribution of the radiotracers was assumed to be in equilibrium at the beginning of the experiment. The blood perfusion was calculated by fitting a two-exponential function to the measuring points. The mean value of the perfusion rate calculated from the xenon results was 13 ± 10 ml/(100 g-min) [range 3 to 38 ml/(100 g-min)] and from the krypton results 19 ± 11 ml/(100 g-min) [range 5 to 45 ml/(100 g-min)]. These values were obtained, if the partition coefficients are equal to one. The equations obtained by using compartmental analysis were used for the calculation of the relative partition coefficient of krypton and xenon. The partition coefficient of krypton was found to be slightly smaller than that of xenon, which may be due to its smaller molecular weight.

Detection of Soluble Fibrin Monomer Complexes in Blood by Means of Protamine Sulphate Test

1968 ◽  
Vol 20 (01/02) ◽  
pp. 044-049 ◽  
Author(s):  
B Lipiński ◽  
K Worowski
Keyword(s):  
Human Subjects ◽  
Coronary Thrombosis ◽  
Mean Value ◽  
Healthy Human ◽  
Protamine Sulphate ◽  
Soluble Fibrin ◽  
Fibrin Monomer ◽  
Dog Plasma ◽  
The Mean ◽  
Precipitable Protein

SummaryIn the present paper described is a simple test for detecting soluble fibrin monomer complexes (SFMC) in blood. The test consists in mixing 1% protamine sulphate with diluted oxalated plasma or serum and reading the optical density at 6190 Å. In experiments with dog plasma, enriched with soluble fibrin complexes, it was shown that OD read in PS test is proportional to the amount of fibrin recovered from the precipitate. It was found that SFMC level in plasma increases in rabbits infused intravenously with thrombin and decreases after injection of plasmin with streptokinase. In both cases PS precipitable protein in serum is elevated indicating enhanced fibrinolysis. In healthy human subjects the mean value of OD readings in plasma and sera were found to be 0.30 and 0.11, while in patients with coronary thrombosis they are 0.64 and 0.05 respectively. The origin of SFMC in circulation under physiological and pathological conditions is discussed.

Detection of Circulating Tissue Factor and Factor VII in a Normal Population

1996 ◽  
Vol 75 (05) ◽  
pp. 772-777 ◽  
Author(s):  
Sybille Albrecht ◽  
Matthias Kotzsch ◽  
Gabriele Siegert ◽  
Thomas Luther ◽  
Heinz Großmann ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Normal Population ◽  
Mean Value ◽  
Factor Vii ◽  
Significant Difference ◽  
Age Dependent ◽  
The Mean ◽  
Highly Correlated ◽  
And Gender

SummaryThe plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 ± 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 ± 15% and the factor VIlag was 0.77 ± 0.19 μg/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.

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